Anatolia, linking Asia and Europe, has a long and distinguished record as a centre of civilization - from one of the world's first towns (Catal Huyuk), through the successive periods of Hittites and Trojans, Ionians and Lydians, Romans and Byzantines.

But the region acquires its present identity and name, as Turkey, more recently - with the arrival of Turkish tribes to confront the Byzantine empire in the 11th century AD.

Byzantines and Turks: 1064-1071

In 1064 the Seljuk Turks, under their sultan Alp Arslan, invade Armenia - for many centuries a disputed frontier region between the Byzantine empire and neighbours to the east. Alp Arslan follows his success here with an attack on Georgia, in 1068. These acts of aggression prompt a response from the Byzantine emperor, Romanus IV Diogenes.

The armies meet in 1071 at Manzikert, near Lake Van. The battle, a resounding victory for the Seljuks, is a turning point in the story of the Byzantine empire. Within a few years there are Turkish tribes in many parts of Anatolia. Some of them are bitter enemies of the Seljuks, but the Seljuks are now the main power in this borderland between Islam and Christianity.

The Seljuks and the sultanate of Rum: 11th - 13th c.

Rum, meaning Rome, is the word used by the Turks for Byzantium (whose officials still describe themselves as Romans, in keeping with the origins of the Byzantine empire). Pressing deep into Anatolia, after the victory at Manzikert in 1071, the Seljuks reach Konya in the following year and Nicaea, much closer to Constantinople, in about 1080. They make Nicaea their capital until it is recovered by the Byzantines during the first crusade, in 1097. In 1099 Konya, strategically placed in the centre of Anatolia, becomes the Seljuk capital.

The Seljuks describe their new territory, at the heart of the old Byzantine empire, as the sultanate of Rum.

Throughout the 12th and 13th century Anatolia is in turmoil. Turkish tribes fight among themselves. The Byzantines try to recover their land. Crusaders, passing through and from 1204 occupying Constantinople, complicate the picture.

But the new and overriding feature is that Anatolia is now largely occupied by Turks. This fact enters the languages of the period. In addition to its many other names, the region begins to be referred to as Turkey - the land of the Turks. The new identity survives the arrival of the Mongols in the 13th century and the end of the Seljuk dynasty in the early 14th century. By then another Turkish tribe, the Ottomans, are making their mark.

The Ottoman Turks: 13th - 14th century

During the 13th century, when many Turkish emirates are being established in Anatolia, a petty chieftain by the name of Ertughrul wins control over a limited area around Sögüt, between Ankara and Constantinople. He is succeeded in about 1285 by his son Osman, whose name is a Turkish version of the Arabic Othman. Through Osman, seen later as founder of the dynasty, his people become known as the Ottoman Turks.

Most of the Turks of Anatolia live in a style in keeping with their origins, as fierce nomads of the steppes. Riding out to war is their everyday activity. But they are also keen Muslims. They see themselves as ghazi, an Arabic word for warrior but with religious connotations.

Turks setting out on a ghaza (armed raid) are indulging in an expedition of plunder but also in a jihad (holy war). It is a potent combination. The enfeebled Byzantine empire to the west of their territory - crippled, ironically, by the Christian fourth crusade - provides the Ottoman Turks with a natural target.

Progress is at first slow. The Ottoman horsemen lack the equipment to take fortified Byzantine towns. Instead they plunder the surrounding countryside, effectively strangling their victims into submission. Bursa, the first important Byzantine stronghold to the west, falls to them in 1326, the year of Osman's death.

After the fall of Bursa the Ottoman advance quickens. Nicaea yields in 1331 and Nicomedia in 1337. In that direction a narrow neck of land leads directly to Constantinople, but the Ottomans prefer a roundabout route. In 1354 they cross into Europe at the other end of the sea of Marmara, capturing Gallipoli. Eight years later Adrianople falls to them, severing the main route westwards from Constantinople.

A stranglehold is being applied to the Byzantine capital itself, but the Turks look first for plunder in an easier direction. They continue westwards into the Balkans, where their successes prompt the formation of the formidable Ottoman fighting force known as the Janissaries.

The Turks in the Balkans: 1389 - 1402

A victory at Kosovo in 1389 brings Serbia under Ottoman control as a vassal state. The Ottoman sultan Murad I dies on the battlefield of Kosovo and is succeeded by his son Bayazid I, whose name Yildirim ('Thunderbolt') reflects his early military successes. The Slav kingdom of Bulgaria is fully occupied by 1393. In the following year Bayazid begins the long expected blockade of Constantinople. A Hungarian army marching as a crusade against the Turks is heavily defeated at Nicopolis in 1396. Meanwhile the sultan campaigns south into Greece. But then the Balkans and Constantinople are given a sudden reprieve.

Bayazid is confronted by a major threat in Anatolia - the arrival of Timur.

The Battle of Ankara: 1402

After destroying Baghdad in 1401, Timur turns his attention to Anatolia. He finds that several emirs are willing to side with him against the Ottoman Turks. Bayazid's armies have been extending the Ottoman empire to the east as well as the west. But his victims to the east have been fellow Muslims, not Christians. There is resentment to be tapped, not that Timur needs much in the way of assistance.

Bayazid meets the threat near Ankara, where his army is heavily defeated. Captured in the battle, he dies as Timur's prisoner in 1403 (legend later provides the indignity of an iron cage).

Retrenchment and recovery: 1402 - 1481

The Ottoman domain shrinks drastically after Bayazid's defeat and capture by Timur in 1402. The many small emirs of Turkey reassert their independence, as do the Balkan states. The three sons of Bayazid are left with only the family's central territories round the southern and western sides of the sea of Marmara. They fight each other in a civil war which is won by the youngest, Mehmed I, in 1413.

From this unpromising position, the son and grandson of Mehmed (Murad II and Mehmed II, whose combined reigns span nearly seventy years) achieve an astonishing recovery for the Ottoman state - posing an ever greater threat to the Byzantine empire.

Murad patiently reasserts control over much of western Anatolia, and makes equivalent headway in the Balkans. Serbia is brought back into the Ottoman fold (Murad marries a Serbian princess in 1433). Much of Bulgaria also is recovered. A strong counter-attack down the Danube in 1443 by an army of Hungarians and Poles is at first successful, until the Ottoman Turks win a decisive victory at Varna in 1444.

This steady process is continued by Murad's son, Mehmed II.

Mehmed II conquers Athens and almost the whole of the Greek peninsula in 1458-60. He then engages in a prolonged war with Venice, winning many valuable ports along the Adriatic coast. In 1463-4 he captures Bosnia where a large number of nobles convert to Islam, unlike neighbouring Serbia which remains largely Greek Orthodox - a distinction with resonance in more recent history. By the time of Mehmed's death, in 1481, Anatolia has also been recovered. Even regions north of the Black Sea are vassal states.

But the achievement which gives Mehmed his title of Fatih (Conqueror), and his secure place in history, has been his capture in 1453 of Constantinople.

Fall of Constantinople: 1453

A month after his twenty-first birthday, in April 1453, Mehmed II applies to Constantinople the stranglehold which has been a tacit threat for nearly a century, ever since the Ottoman capture of Adrianople (Edirne in its Turkish name) in 1362. He initiates a tight blockade of the city by both sea and land.

The inhabitants, as often before, place their faith in their immensely strong city walls. Only on the harbour side are these walls vulnerable, and the harbour (the long creek known as the Golden Horn) is protected by a great chain preventing enemy ships from entering. But the young sultan has an answer to that.

At dawn, one Sunday morning in May, the defenders on the walls are surprised to see Muslim ships in the harbour. During the night they have been dragged on wheeled carriages, on a temporary wooden roadway, over a 200-foot hill. Over the next few days cannon are moved into place, including one 19-ton bombard. At sunset on May 28 the attack begins. Every bell in the city rings the alarm. Santa Sophia is full of people praying and singing Kyrie Eleison (Lord, have mercy).

By dawn the Turks are in the city. The last Byzantine emperor, Constantine XI, has died in the fighting.

Mehmed, the sultan, goes straight to Santa Sophia to hear a proclamation from the pulpit - that there is no God but Allah, and Muhammad is his prophet. The great church, for many centuries the most magnificent in Christendom, now begins its career as a mosque. And Constantinople gradually acquires a new name; the urban area, widely referred to in everyday Greek as eis tin polin (in the city), becomes Istanbul.

The Ottoman army is allowed three days of pillage (a depressing convention of medieval warfare), but Mehmed keeps it under tolerable control. He has acquired a capital for his empire. He intends to preserve and improve it.

In an honourable Muslim tradition, he plans a multicultural and tolerant city. The population is much reduced, after decades of fear and uncertainty, so Mehmed brings Greeks from the Aegean (soon another part of his domain) to revive the place. The Greek Orthodox patriarch is left in charge of his flock. And when the Jews in Spain are expelled, in 1492, many of them come to Istanbul where it is official policy to welcome them.

Mehmed launches into a busy building programme, founding several mosques and beginning Topkapi Sarayi in 1462 as his own palace. Constantinople, transformed into Istanbul, is set to be a great imperial centre again. It has exchanged one empire for another, Byzantine for Ottoman.